I was an electrician 20 years ago. We used to cut into PVC with a
string but it was done when the pipe was empty.

My nephew is now working with PVC for fiber. He said that they cut
into a pipe they thought was empty and it turned out it contained a
fiber optics cable.

I was just wondering if you could wrap a string around a PVC pipe and
keep tension on the spool and drive the cutting with an electric drill
pulling the string?

I wonder how much success you could have in scoring around the pipe
enough to break it in case it is not empty.